Page:Popular Science Monthly Volume 45.djvu/579

Rh into others as varieties or subvarieties. Many of these species, furthermore, were made by keen observers who devoted their whole time to mailing them, and were adepts at the work, and yet in the light of the studies of Baird, Coues, Allen, Ridgway, Brewer, and others these specific distinctions have been broken down, and many of these formerly well-recognized species are now known as geographical varieties.

His work is filled with a large number of cases of deformation, atrophy, hypertrophy, duplication of parts, etc. Varietal groups are one thing; double-headed monsters, supernumerary digits, etc., are quite another thing, and no one has ever been tempted to look in that direction for new species; indeed, the collector has rarely been inclined to save such freaks, and so Mr. Bateson's book is all the more remarkable for presenting such a large array of material.

After turning the last page we say to ourselves, If such profound structural divergencies can arise, how elastic the organism must be, and how infinite must be the number of minor variations of strength, endurance, color, proclivities, etc., which is all the material the Darwinian demands to sustain the doctrine of natural selection as an all-sufficient cause!

opening volume of the Columbian Knowledge Series is a remarkably picturesque book. Dealing with those impressive moments, of infrequent occurrence in any one locality, when the face of Nature seems transformed, it appeals strongly to popular interest. Moreover, the fact that these occasions afford rare and precious opportunities for valuable scientific observations makes the subject doubly attractive to all intelligent minds. Mrs. Todd has made excellent use of her opportunities. With rare powers of description she tells how eclipses occur, describes their phenomena, and relates the incidents of various expeditious for observation. A historical sketch of eclipses from the remote past down to 1893 is given. Considerable is told about instruments and photographic appliances used in observing eclipses. A notably interesting feature is a list of future total eclipses of the sun, with a chart showing where they will be visible, and there is a similar list and chart of past eclipses since 1842. The proofs of the book have passed under the scrutiny of Prof. C. A. Young as well as that of Prof. Todd, so that readers need have no fears of inaccuracies. The volume is copiously illustrated and has an index.

volume of Lord Kelvin's Popular Lectures now issued completes the set of three volumes. Among the subjects discussed in the geological papers and addresses are geological time, geological dynamics and climate, the doctrine of uniformity, the internal condition of the earth, and polar icecaps. In one of the addresses delivered before the British Association, Lord Kelvin has discussed the sources of available energy in Nature, designating them briefly as tides, food, fuel, wind, and rain, all but the first of which are derived from the sun. There are also addresses, more general in character, delivered at the opening of the Bangor laboratories, at the unveiling of a statue of Joule, and at three anniversary meetings of the Royal Society.

essential fact regarding the public libraries of America is here told in brief compass by the eminent librarian of Amherst College. The claims of the public library as a means of refined entertainment, as a gainful partner to the school, the workshop, and the studio, as here set forth, are certainly weighty enough for national conviction. To the public-spirited men and women who either wish to improve a library already established, or who desire to found one, Mr. Fletcher's chapters are indispensable. He concisely passes in review the selection of books, their fit housing, and the management of a library, this last task now much lightened for trustees and